Sökning: "chromium oxide"

Visar resultat 1 - 5 av 69 avhandlingar innehållade orden chromium oxide.

  1. 1. Measurements of the thermodynamic activities of chromium  and vanadium oxides in CaO-MgO-Al2O3-SiO2 slags

    Författare :Pengli Dong; Seshadri Seetharaman; Mselly Mbwambo Nzotta; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermodynamic activity; chromium oxide; vanadium oxide; equilibrium; slags; slag basicity; gas-equilibration technique; Metallurgical process engineering; Metallurgisk processteknik;

    Sammanfattning : In the present work, the thermodynamic activities of chromium and vanadium oxide in CaO-SiO2-MgO-Al2O3 slags were measured using gas-slag equilibration technique. The slag was equilibrated with a gas mixture of CO, CO2 and Ar gases enabling well-defined oxygen partial pressures in the gas mixture (PO2=10-3,10-4,10-5 Pa) at temperatures 1803, 1823K, 1873, 1923 K. LÄS MER

  2. 2. Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel powder

    Författare :Ola Bergman; John Ågren; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; powder metallurgy; chromium; pre-alloying; surface oxides; sintering; Materials science; Teknisk materialvetenskap;

    Sammanfattning : The powder metallurgy (PM) process route is very competitive for mass production of structural steel components with complex shape, due to efficient material utilisation, low energy consumption, and short overall production time. The most commonly used alloying elements are the processing friendly metals Cu, Ni and Mo. LÄS MER

  3. 3. The rule of hydrogen and rare earth metals in the formation of protective metal-oxides

    Författare :Bent N. Tveten; KTH; []
    Nyckelord :chromium; high-temperature corrosion; oxide growth; scale adherence; hydrogen; yttria; REM; reactive element effect; gas phase analysis;

    Sammanfattning : The effects of hydrogen and rare earth metal (REM) additionson the oxidation behavior of metals and alloys that formchromia, alumina and zirconia in 20 mbar O2and/or H2O have been investigated at elevated temperatures.The metal-gas reactions were studied by the use of isotopicallylabeled gas in combination with mass spectrometry and bymeasuring changes in the total pressure in a closed reactionchamber. LÄS MER

  4. 4. Bioaccessibility of Stainless Steels : Importance of Bulk and Surface Features

    Författare :Gunilla Herting; Inger Odnevall Wallinder; Stuart Lyon; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Stainless steel; iron; chromium; nickel; corrosion; metal release; artificial rain; synthetic body fluids; acetic acid; surface oxide; surface finish; Surface and colloid chemistry; Yt- och kolloidkemi;

    Sammanfattning : With increasing environmental awareness, the desire to protect human beings and the environment from adverse effects induced by dispersed metals has become an issue of great concern and interest. New policies, such as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) within the European Community, have been implemented to reduce hazards posed by the use of chemicals on producers and downstream users. LÄS MER

  5. 5. Metallic materials in Solid Oxide Fuel Cells: Oxidation and chromium evaporation properties

    Författare :Mareddy Reddy; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; Interconnect; SOFC; High temperature corrosion; Balance of Plant; Chromium evaporation;

    Sammanfattning : Solid oxide fuel cells (SOFCs) are high-temperature energy conversion devices which have great potential due to their high efficiency, low operating costs and flexibility in using conventional hydrocarbon based fuels. However, system cost, durability and performance stability in long-term operation are barriers to the widespread commercialization of SOFC technology. LÄS MER